Reactive power compensation rpc offers the most economic mean s to do so. The voltage on customer side will decrease further. In the first quarter part of ac cycle, capacitor or reactor stores the reactive power var and in the next quarter cycle, the reactive power gets returned back to the ac power source. Dynamic reactive compensation and hvdc transmission brian k. The issues of reactive power compensation in highvoltage transmission lines authors zbigniew lubosny jacek klucznik krzysztof dobrzynski keywords reactive power compensation, overhead lines, shunt reactor abstract this paper discusses the selection of compensation shunt reactors for a doublecircuit 400 kv transmission line using the example. Power, as we know, consists of two components, active and reactive power. All the arrangements in electrical pomes system are done to meet up this basic requirement. Reactive power is produced when the current waveform is out of phase with the voltage waveform due to inductive current lags voltage and capacitive current leads voltage loads and is measured in voltampere reactive var.
Reactive power compensation in a power system is of two typesshunt and series. Ac power supply systems produce and consume two types of powers. The total sum of active and reactive power is called as apparent power. Effect of series and shunt compensation on voltage stability. The reactive power compensation and voltage control training course essentially encourages you to understand the physical importance of reactive power, basics of reactive power compensations, distinctive answers for reactive power compensation, idea. The issues of reactive power compensation in highvoltage. How reactive power is helpful to maintain a system healthy. Reactivepower control in electrical power transmission. It is meant to enhance controllability and increase power transfer capability of the network. Effect of reactive power compensation on voltage profile. Because underground line capacitance for power cables is far higher than overhead line capacitance.
Until a few years ago, the ability to generate reactive power was largely taken for granted in pjm. A flexible alternating current transmission system facts is a system composed of static equipment used for the ac transmission of electrical energy. The reactive power is essential for creating the needed coupling fields for energy devices. Power factor is nothing but the ratio of real power to apparent power. Local control of voltage by means of auto transformers will lead to increase of current to get the same power and this in turn will increase voltage drops in lines. Reactive power inductive load and power factor calculation duration. At high levels of load, however, transmission lines absorb reactive power and thereby lower voltages. In this paper the effect of line reactive power flow on transmission efficiency, voltage regulation and power factor with and without var compensation techniques are analyzed and presented. For improving the performance of a ac power system, the reactive is to be managed in a efficient way, this is known as reactive power compensation.
It is desirable that the voltage in power system should be 1 per unit pu everywhere but it is highly impossible to maintain it. Previously, the stress has been eased by adding more generation facilities to the grid and by building additional transmission lines. Apart from being var generators, transformers provide a convenient means of controlling real power, and reactive power flow along a transmission line. It improves the power transfer capability of the line. The shunt inverter is operated in such a way as to demand this dc. For a reliable and stable operation of the power syst. Fundamental concepts of reactive compensation hvdc. Reactive power q var is needed for a proper functioning ac power system to keep the voltage up and is related to the active power p kw and apparent power s kva through the power triangle. Sometime for sinusoidal wave the power factor is defined as the cosine of angle between voltage and current in this article we are going to see entire study about power factor. Pdf reactive power compensation and voltage control. In other words, in series compensation, reactive power is inserted in series with the transmission line for improving the impedance of the system. Facts controls on the reactive power compensation, which supports voltage recovery. If the transmitted power is above sk, the line will introduce additionally inductive reactive power, and if it is below sk, the line will introduce capacitive reactive power. It is mostly used in extra and ultra high voltage line.
Pdf reactive power compensation in power transmission. The advantages of reactive power compensation are improved power factor, voltage balancing, and. The demand for active power is expressed in kilowatts kw or mega watts mw. It is almost universal for some of the reactive load to be compensated locally as power factor correction. The configuration of reactive power compensation equipment shall follow the principles as detailed below. It is generally a power electronicsbased system facts is defined by the ieee as a power electronic based system and other static. Shunt compensation an overview sciencedirect topics. Under light load, the line generates more reactive power than it consumes. The reactive power generated by the compensator, q p, is generally given by the relation q p i c v c i c v. Also generally induction load consists of two current. Reactive power compensation techniques in transmission. Load compensation is the management of the reactive power to improve the quality of the supply in ac power systems 5. Pdf reactive power compensation in a distribution system using. Reactive power var compensation is defined as the management of reactive power to improve the performance of ac systems.
Importance of reactive power in power generation and. Transmission of reactive power will load more the lines, which in turn will introduce more reactive power. This power should be supplied from electrical generating station. A study of reactive power compensation in power system. Such interfaces measure power flows across select high voltage transmission lines into remote load centers to indicate when additional local generation within the load center is necessary to maintain voltage levels. Analysis of reactive power in power system electrical. By artificial injection of reactive power to the loads relieves the transmission network from reactive power flow and improves both the transmission efficiency and operating power. Var compensation near load centre has gained more importance in recent times. The voltage can be controlled by providing reactive power control margin to modulate the supply needs through the following compensations as given below. Reactive power compensation reactive power can be stated as the amount of unused power that is developed by reactive components, such as inductors or capacitors in an ac circuits. A thyristor switched capacitor tsc is used to inject capacitive reactive power step by step, if called for by transient phenomena during switchon.
Shunt compensation can be installed near the load, in a distribution substation, along the distribution feeder, or in a transmission substation. Reactive power var compensation is nothing but the control of reactive power to enhance the performance of ac system. Reactive power compensation in transmission line by using. A static synchronous compensator statcom is a regulating device used on alternating current. Reactive power is an essential component of ac electric power systems. The increasing power demand of the modern world contributes to the increased stress on the power system. Instead of being controlled continuously, they are switched on and off when needed. Reactive power uncompensated transmission lines passive compensa reactivepower control in electrical power transmission systems wileyieee press books ieee websites place cookies on your device to give you the best user experience.
Control of reactive power and magnitude of voltage is almost corelated words. Reactive power control in electrical power transmission. Importance of reactive power for system electrical notes. Reactive power loads must be supplied either locally from customerowned devices or from the system itself. As has already been clarified, real power is controlled by means of shifting the phase of voltage, and reactive power by changing its magnitude. Shunt reactive compensation can be inductive or capacitive. It accomplishes useful work like lighting lamps, rotating motors, etc. Although in alternating power system, reactive power always comes in to picture. What are the advantages, disadvantages and applications of. Why is reactive power compensation needed in a power. Power factor improvement reactive power compensation.
Capacitor bank reactive power compensation electrical4u. Reactive compensation enspec power renewables voltage. The maximum transmissible power is 2 v 2 x, twice the steadystate limit of the uncompensated line. Reactive power compensation by appropriate means has become the most economically attractive and effective solution technically for both traditional and new problems at different voltage levels in a power system. To know the effect of series and shunt compensation on voltage stability, first of all we will have some discussion on compensation technique. Reactive power compensation techniques in transmission lines. Reactive power compensation in transmission systems also improves the stability of the ac system by increasing the maximum active power that can be transmitted. Reactive power compensation of transmission lines by.
Pdf reactive power compensation of transmission lines. The reactive power is electronically provided by the series inverter, and the active power is transmitted to the dc terminals. Under surge impedance loading, the line generates and consumes the same amount of reactive power. More power plants, substations, and transmission lines need to be constructed. The ability to control or compensate reactive power has many benefits. If the power demand is less than reactive power supplied, the load voltage rises to a higher level which leads to automatic tripping of transmission equipment, low power factor, insulation failures of the cables and windings of various mechanical devices to overcome this, additional reactive power available on the system must be compensated. Why do underground cables require a higher degree of reactive power compensation than overhead lines. A reactive power compensation strategy for voltage. Voltage support is generally required to reduce voltage fluctuation at a given terminal of a transmission line. Static var compensators svc portfolio siemens global. So, this inverter will exchange active and reactive power with the line.
In this thesis statcom is used for reactive power compensation on electric transmission line. Real power or active power is the true power given to any load. Power factor is a measure of the relation between real and reactive power. Reactive power compensation for transmission and distribution. Reactive power generationconsumption note that a transmission line both absorbs and generates reactive power. Compensation in transmission level with the use of such systems are costly. Power loss and dispersion transmission lines may also be dispersive, which means the propagation velocity on the line is not constant with frequency for example the frequency components of square wave recall odd harmonics only each propagate at a different velocity. Reactive power compensation device industry market in china research, 20142018 currently, power quality reduction resulting from harmonic wave and reactive power in chinas electrical power system has become the most prominent problem of chinas power grid, so more and more attention has been paid to harmonic suppression and reactive power compensation. In this paper, the reactive power compensation to maintain rated voltage at the bus. Yongan deng, masc student at concordia university 1. Lv reactive power compensation equipment serves to balance the reactive power of transmission lines when transmitting different active power to maintain terminal voltage of the uhv lines within a reasonable range. It constitutes voltage and current loading of circuits but does not result in an average active power consumption and is, in fact, an important component in all ac power networks.
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